There is a large variety of long-lasting bakery-type snacks with fillings on the market. The majority of these consist of dry cookie or dry biscuit-type dough as carrier combined with a fat-based filling. Beyond that there are also filled sponge-cake-type snacks or soft biscuit sandwiches, which are assembled with water or milk-containing fillings. These snacks have a higher moisture and are therefore of limited shelf life often requiring refrigerated or frozen storage conditions. The water activities (Aw) for these snacks range from Aw<0.6 for dry cookie-type sandwiches to around Aw 0.85 to 0.90 for the sponge-cake-type products.
Established processes for making baked goods carriers are basically applying bulk dough preparation and dough sheeting or depositing techniques. Desired shapes are cut out of the raw dough sheets and are freely baked like cookies, or the whole dough sheet is baked on a band oven. From this, a filled snack is created by laminating at least two baked sheets with a filling in-between followed by a cutting operation. In addition to many other processes which are too numerous to mention at this stage, baking in moulds is very common. A defined portion of raw dough is deposited into baking moulds to provide consistently shaped baked products after baking.
The dough recipes and mixing techniques provide the desired dough carrier texture. Most snack carrier dough recipes contain baking powders, and the preparation involves aeration steps during mixing or fat-layer lamination techniques in combination with a controlled baking process. Snack carriers with defined constant shapes are preferably made by using moulds, which help to control the dough shape during baking. Available dough carriers with a cavity made according to this process are fairly dry in taste and have relatively high fat and sugar contents. Their main application is for sweet chocolate snack assembling. There is no indication in literature or from industry that even shaped snack carriers with a cavity are being made or have been attempted by using a yeast or rye bread dough. The major problem in providing yeast dough-based snack carriers with a cavity is the fact that the rise of the dough in the mould is difficult to control.
Shaped fresh-baked loaves of bread are commonly offered in sizes around 0.5 to 1 kg. They are yeast-dough based and deliver a high ratio of crumb versus crust when baked in moulds or casings. The water activities (Aw) of fresh-baked toast bread would be around 0.94 to 0.96 and of fresh rye bread around 0.95 to 0.98. Attempts to create small 20 to 30 g snack carriers with a cavity using white or rye bread dough via mould baking provided a dry and crusty product with a low crumb content and therefore having a water activity of Aw<0.9. Resulting products were significantly different in taste and texture to bulk-baked white, rye or brioche-type bread.
Fresh-baked bread loaves have water activities around Aw=0.94 to 0.97. They are very suitable for the creation of snacks with a short shelf life when combined with moist fillings such as cheese or sausage (Aw=0.96 to 0.99). Accordingly, filled sandwiches made from sliced bread last only about 3 to 6 days. Providing a cheese-filled snack with the use of drier dough carriers (e.g. Aw<0.85) would lead to a significant moisture migration from the cheese into the dough with major impact on the overall quality and shelf life. This is especially the case when using biscuit-type carriers baked in moulds because their water activity tends to be lower (Aw<0.8). Bulk-baked fresh biscuit dough sheets provide an Aw=0.88 to 0.92 and available filled sandwich-type products deliver a much fresher taste when fillings have around the same water activity. From this aspect it is considered very advantageous if a small handheld individually-shaped and appealing dough carrier could be delivered at Aw=0.90 to 0.92 without undergoing the known dough sheeting and cutting process. It would be even more advantageous if this snack were lower in dietary calories than snacks available on the market. This could be achieved by using yeast dough instead of-biscuit-based carriers with moist fillings because yeast dough has overall lower fat and sugar contents.
EP 1,256,280 describes a process for making bread snacks with fillings of high water content and shelf lives at chilled or ambient temperatures of more than six weeks, wherein ground baked bread is used as raw material. The process is described as being especially useful for rye bread and involves the following steps:
(i) the baked bread is ground,
(ii) water is added to the ground bread to improve its extrudability and to adjust its water activity to about 0.95 to 0.98 or higher,
(iii) the bread/water mixture is kneaded to a bread dough,
(iv) the bread dough is coextruded with the filling and
(v) the snacks are formed, packed and pasteurized.
In this known process, the snack shape is created via a continuous pressure-forming process through a nozzle, where a filling is simultaneously inserted into the dough carrier (co-extrusion). The equipment proposed for this is a Rheon KN 400 extruder, which applies relatively low extrusion pressures. The provided products are fully enrobed (closed) filled snacks. Because of this closed snack system, it is therefore possible to pasteurize the complete product, which is recommended and required to reduce eventual yeast or mould contamination especially when, as claimed, delivering long-lasting quality. The patented process works most preferably with moist rye bread (Aw=0.95-0.98).
A disadvantage of low extrusion pressure originating in a Rheon is that it is very difficult to push through drier crumbs e.g. derived from white bread with water activities at 0.94 to 0.96, especially when no glycerin is added to the crumbs. Glycerin acts as a means of balancing water activity and moisture but it can give an unpleasant taste to the bread. It would be beneficial to prevent the use of glycerin in dough-enrobed snacks. Experimental trials with white bread crumbs without glycerin and no added water resulted in clogging of the Rheon extruder especially after stop/start operations. Any casing created was not stable enough to hold the filling because the crumbs did not stick together. Further trials with a higher shear extruder such as a Bosch WEF 1050 using dry white bread or rye bread or even biscuit type crumbs have shown that it was feasible to form a stable doughy casing but the dough texture lost its original structure completely. The product would be unacceptable to a consumer. The limitations of the approach indicated in EP 1,256,280 are that the products provided are fully enrobed snacks, which means that the filling of the snack is not visible to the consumer and white bread-type snacks are only feasible by adding significant amounts of unpleasant-tasting glycerin.
The problem underlying the present invention is to provide a process with which it is possible to manufacture shelf-stable snacks from all different types of bread with a visible filling and without glycerin addition.